Such a roller is known from European Patent 452 633 A1. In this document, no mention is made of the particularly close sequence of the individual supporting elements. Each supporting element has an actual force-exerting main bearing pocket. Bearing pockets with a considerably smaller diameter than the main bearing pocket, understood as stabilizing bearing pockets, are arranged outside the main bearing pocket, and arc supplied with hydraulic fluid through throttling ports. When such a stabilizing bearing pocket is slightly lifted from the internal perimeter of the hollow roller, the hydrostatic pressure collapses in this bearing pocket due to the throttling. This causes the edge of the bearing pocket and thus the supporting element at this point to come closer to the internal perimeter of the hollow roller, thus reducing the flow cross-section and increasing the pressure. Finally an equilibrium is achieved where the stabilizing bearing pocket is held at a certain distance from the inner perimeter of the hollow roller. With four such stabilizing bearing pockets, the entire supporting element and the main bearing pocket are always held in the correct position in relation to the inner perimeter of the hollow roller.
In the known embodiment, the main bearing pocket has a circular cross-section, whose diameter is only slightly less than the dimension of the supporting element in the longitudinal direction of the roller. Since the hollow roller is made of steel or cast iron, the cross-section of the bearing pocket presents no problem in the known embodiment.
In tests with flexible hollow rollers, such as rollers made of fiber-reinforced plastic, which may provide a particularly good fit with a mating roller, it has been established that at higher line forces, the pass line tends to dent the hollow roller and press it into the bearing pocket. Even if such denting is small, it results in pressure on the edges of the circumferential webs thus causing increased friction on the edges of the webs and increased wear.